JPH0329299Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Field of Application] The present invention relates to a combined body in which a ceramic member constituting a turbo rotor and a metal member constituting a rotating shaft are fitted and fastened by filling only brazing material. [Prior Art] In recent years, ceramic members with excellent mechanical strength, heat resistance, and wear resistance and low specific gravity, especially zirconia, silicon carbide, Sintered bodies such as SiAlON silicon nitride are suitable, but they have difficulties in processability, making it difficult to use the above ceramic members alone as mechanical parts, and applications where high loads are applied, such as turbochargers and gas turbine engines. It has been attracting attention that the rotation shafts of these machines are made of metal members with high strength and excellent workability, and that they are combined with the above-mentioned ceramic members to create a composite structure. body has been studied and proposed. Conventionally, when joining a ceramic member and a metal member, a method has often been adopted in which first metal plating or metallization is applied to the joint portion of the ceramic member, and then the ceramic member and the metal member are joined by brazing. was. In particular, when a ceramic member and a metal member are jointed together, the ceramic member and the metal member are generally required to have high coaxiality, so the joint portion of the ceramic member is generally polished. (Problem to be solved by the invention) However, in the case of such a conventional brazed joint of a ceramic member and a metal member, after polishing the joint of the ceramic member, a metallizing layer is applied to the joint. When a shaft joint is constructed by brazing the formed ceramic member and metal member,
For example, when a ceramic turbo rotor and a metal rotating shaft are joined by a shaft joint, variations in shaft diameter, squareness, roundness, etc. will be extremely small, and as a result, variations in the gap between the ceramic member and the metal member will also be small. However, since it is difficult to apply metallization to a uniform thickness over the entire joint area of ceramic parts, the metallization layer is eaten away and disappears during brazing in the thin parts. , the wettability of the brazing material deteriorates and defects such as cavities are likely to occur, resulting in a decrease in bonding strength. In addition, the adhesion strength between the bonded part of the polished ceramic member and the metallizing layer was lower than that of the fired surface, and the brazing strength between the ceramic member and the metal member was low and unstable. If a metallizing layer is formed on the fired surface and a shaft joint is constructed by brazing the ceramic member and the metal member, there will be large variations in shaft diameter, squareness, roundness, etc. Therefore, the hole diameter of the metal member must be machined to a large size, and the gap between each ceramic member and metal member increases, resulting in low and unstable bonding strength.
The bonding between the ceramic member and the metal member becomes less reliable. [Means for solving the problems] The present invention was devised as a result of various experiments in view of the above-mentioned drawbacks. By polishing the gap between the two to within a maximum of 150 μm so as not to impair accuracy such as roundness,
Even without forming a metal layer at the joint portion of the ceramic member, the portion where the ceramic member is fitted into the metal member is uniformly filled with brazing material, and as a result, the metal layer is provided on the ceramic member and brazing is performed. It was found that there was no difference in bonding strength from the conventional example. Therefore, in the present invention, a part of the ceramic member forming the turbo rotor, which has been polished to have a gap of 20 to 110 μm with respect to the hole formed in the metal member forming the rotating shaft, is inserted into the hole, and the ceramic member forming the turbo rotor is inserted into the hole. A combined body of a ceramic member and a metal member is provided, characterized in that only a brazing material is filled between the surface of the ceramic member and the surface of the metal member in the insertion portion, and the ceramic member is fastened with the metal member. [Example] Hereinafter, the present invention will be specifically explained in detail with reference to Examples. FIG. 1 is a sectional view showing an embodiment of the combined body of the present invention. 1 is a ceramic member forming a turbo rotor, 2 is a metal member forming a rotating shaft, and a hole is formed inside the metal member 2. The outer surface of the ceramic member 1 is polished and the metal member 2 is connected to the ceramic member 1 by filling only the brazing material 3 with the metal member 2. In order to obtain such a structure, first, a ceramic member 1 made of a silicon nitride ceramic sintered body having a cylindrical cross section with a diameter of approximately 13 mm as shown in FIG. 2 was manufactured by an atmospheric pressure sintering method. Next, the joint part of the ceramic member 1 with the metal member was polished using three types of diamond anchor stones of #120, #140, and #170 standards, and three types of surface roughness were set for the joint part, and When the joint part is fitted into the metal member 2, which is made of a ring made of a heat-resistant low-expansion alloy with an outer diameter of 17 mm equivalent to Incoloy 903, the gap with respect to the metal member 2 is 20, 30,
The dimensions were set to 60, 90, and 110 μm. In addition,
Two types of surface roughness were set for the inner diameter surface of the metal member 2 by cutting and finishing. Next, the ceramic member 1 was cleaned using an organic solvent such as acetone and then heat treated at 950°C in a forming gas atmosphere, while the metal member 2 was cleaned using an organic solvent such as acetone and then heated to a thickness of approximately 10 μm. Nickel plating has been applied. The ceramic member 1 subjected to the above pretreatment is inserted into the metal member 2, and a high melting point wax of BAg8 standard is poured in at 820°C in an arm gas atmosphere using a high frequency induction heating method, thereby forming the ceramic member 1 and the heat resistant low expansion material. A metal member 2 made of an alloy ring was fastened only with high melting point solder 3. It was confirmed by X-ray radiography and ultrasonic flaw detection that the joint was uniformly filled with brazing material without defects such as cavities. As shown in FIG. 2, the combined body manufactured as described above includes a metal member 2 made of a ring made of a heat-resistant low-expansion alloy.
While supported by a steel cylindrical jig 4, a load is applied to the ceramic member 1 in the direction shown by the arrow via a steel push rod jig 5 in an atmosphere heated to 500°C, and the ceramic member 1 is removed from the metal member 2. The extraction strength was measured and used as the bonding strength between the two. In addition, the surface roughness Ra of the joint between the ceramic member 1 and the metal member 2 with the gap set as described above was measured using a universal surface profile measuring machine.
The outer diameter of the joint of the metal member 2 was measured using a micrometer, and the inner diameter of the joint of the metal member 2 was measured using a three-dimensional coordinate measuring device. The above results are the first
It is shown in Table-1 and Table 1-2. In addition, after polishing the joint of the ceramic member 1 using two types of diamond grindstones of #120 and #170 standards and setting two types of surface roughness of the joint, the joint was coated with 70% Ni and Mn3. %, TiO2 ₂ %,
Using a metallized composition consisting of 6% butyl acetate and 19% glass, in a forming gas atmosphere.
A metal layer was formed at a temperature of 950°C, nickel plating with a thickness of about 10 μm was applied on the metal layer, and the metal member 2 made of a ring made of a heat-resistant low expansion alloy was fitted and brazed in the same manner as described above. A comparative example of the conjugate (sample no.
27, 28).

[Effect of idea]

As explained above in detail, the combined body of the present invention inserts the ceramic member into the metal member, fills only the brazing material, and fastens the ceramic member without forming a metal layer in the part where the ceramic member is to be joined to the metal member. With this structure, it is possible to ensure the reliability of the bonding between the ceramic member and the metal member without impairing the bonding strength, and it is also possible to significantly shorten the manufacturing process. In addition, the coaxiality between the ceramic member and the metal member,
By ensuring the accuracy of the shaft diameter, squareness and roundness of the ceramic members, and in particular ensuring the accuracy of coaxiality, processing after joining can be made extremely simple.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the combined body of the present invention, and FIG. 2 is an explanatory diagram of a method for measuring the extraction strength of the combined body. 1...Ceramic member, 2...Metal member, 3...
... wax wood.

Claims (1)

[Scope of utility model registration request] 20 for the hole formed in the metal member that forms the rotating shaft
A part of the ceramic member constituting the turbo rotor that has been polished to have a gap of ~110 μm is inserted into the hole, and a brazing material is filled between the surface of the ceramic member and the surface of the metal member in the inserted part to close the ceramic member. A combination of a ceramic member and a metal member, characterized in that they are fastened together using a metal member.